Having learned its lesson the hard way with Windows Vista, Microsoft offered assurances Thursday that its upcoming Windows 8 operating system won't require users to buy a new PC.

Having learned its lesson the hard way with Windows Vista, Microsoft offered assurances Thursday that its upcoming Windows 8 operating system won't require users to buy a new PC.

"We've extended the trend we started with Windows 7, of keeping our system requirements either flat or reducing them over time. So Windows 8 will be able to run on a wide range of machines because it will have the same system requirements or lower" as Windows 7, said Michael Angiulo, the Microsoft executive who showed the new software at a press event in Taipei on Thursday.

"Another thing we did is build intelligence into Windows 8 to adapt the user interface based on what hardware you have. So whether you're upgrading or buying a new PC, Windows will adapt itself for your hardware," he said.

The new OS is designed to be touch-enabled, so people without touch screens obviously won't get all the benefits of the new OS. It will also work with a wider variety of sensors for detecting things like motion and proximity, and those sensors will not be present in existing PCs.

But Angiulo said the new interface, which has large colored icons and resembles Windows Phone 7, can still be navigated smoothly using a mouse and a keyboard. The page up and page down buttons can move through the application tiles on the screen, a mouse click will open applications, and the Windows shortcut key on a keyboard will take users back to the desktop.

To prove the point he showed Windows 8 running on a handful of existing PCs, including a Samsung Series 9 laptop and an L Series Sony Vaio.

"When you're reimagining a system that a billion people around the world use it's a big responsibility," Angiulo said. "Windows 8 is for hundreds of millions of computers with all different screen sizes, whether they're touch-enabled or not. Windows 8 is an upgrade for the entire ecosystem of PCs."

It's an important message for Microsoft to get across. If people believe they need to buy a new PC to run Windows 8 it would slow the transition to the new OS and hurt Microsoft's business.

Still, there are features in Windows 8 that won't work with existing hardware, and Microsoft is being more prescriptive than usual about how hardware makers should design their PCs for the new OS.

The optimal screen will have 16:9 aspect ratio and minimum resolution of 1366 by 768 pixels, Angiulo said. A 1024x768 display will also be able to show the new interface, he said. But a netbook with a low-resolution screen will have to switch to the standard desktop mode, he said.

Microsoft learned its lesson about system requirements with Vista. Many PCs in use at the time wouldn't run the OS properly. People reported a lousy experience with the software and it became about the most unpopular OS in Microsoft's history. The company will be keen not to let that happen again.